This inventon relates to centralized door-locking systems in motor vehicles, and, in particular, to a centralised door-locking system in a motor vehicle having a door for a driver of the vehicle, one or more doors providing access for passengers in the vehicle, and a tailgate providing access to a luggage compartment of the vehicle, in which system lockable latches are provided on all of the doors and on the tailgate, the lockable latches on at least the driver's door and the tailgate being key-operable lockable latches, and said lockable latches are interconnected by a switchable actuation system responsive to electrical signals generated by the key-operable lockable latches, said door-locking system being operable; (a) to lock all of the lockable latches in response to the actuation of the key-operable lockable latch of the driver's door in one direction using a key; (b) to unlock all of the lockable latches in response to actuation of the key-operable lockable latch of the driver's door in the opposite direction by said key; and (c) to lock all of the lockable latches in response to actuation of the key-operable lockable latch of the tailgate in one direction by said key.
In such a centralised door-locking system, it is possible to lock or unlock all of the doors and tailgate of a motor vehicle equipped with the system by the acutuation of the lockable latch of the driver's door using a key, and to lock all of the doors of the vehicle and the tailgate by actuation of the lockable latch of the tailgate with a key. Such a system is highly convenient to users of the vehicle, particularly when the vehicle is parked in an exposed position in bad weather conditions, or the vehicle has been parked and the last things to be removed from the vehicle comprise items from the luggage compartment of the vehicle.
However, the aforesaid centralised door-locking systems, convenient though they are, inevitably unlock all the doors of the vehicle when unlocking the driver's door, and this may not always be desired by the driver. The present invention overcomes this disadvantage by modifying such a centralised door-locking system so that a driver of the vehicle can selectively unlock the vehicle doors without losing any of the advantages of such a centralised door-locking system.